Glaucoma is a disease in which the optic nerve is damaged, leading to progressive, irreversible loss of vision. It is typically associated with increased pressure of the fluid (i.e., aqueous humor) in the eye. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness. Once lost, this damaged visual field cannot be recovered. Glaucoma is the second leading cause of blindness in the world, affecting 1 in 200 people under the age of fifty, and 1 in 10 over the age of eighty for a total of approximately 70 million people worldwide.
The importance of lowering intraocular pressure (IOP) in delaying glaucomatous progression has been well documented. When drug therapy fails, or is not tolerated, surgical intervention is warranted. Surgical filtration methods for lowering intraocular pressure by creating a fluid flow-path between the anterior chamber and the subconjunctival tissue have been described. One particular ab interno glaucoma filtration method has been described whereby an intraocular shunt is implanted by directing a needle which holds the shunt through the cornea, across the anterior chamber, and through the trabecular meshwork and sclera, and into the subconjunctival space. See, for example, U.S. Pat. No. 6,544,249, U.S. patent application publication number 2008/0108933, and U.S. Pat. No. 6,007,511. Avoiding damage to the conjunctiva (e.g., subconjunctival blebbing which leads to conjunctival leakage, infections, and endophthalmitis) is critical in determining the success or failure of subconjunctival glaucoma filtration surgery.
To avoid the risk of damaging the conjunctiva, methods have been developed for implanting shunts in the suprachoroidal space. Such methods generally involve implanting rigid shunts that need to be anchored to tissue adjacent to the suprachoroidal space. Implanting a rigid shunt into the suprachoroidal space may result in the shunt producing a cyclodialysis cleft, or separation of the ciliary body from the scleral spur, creating hypotony by allowing the uncontrolled escape of aqueous humor through the cleft into the suprachoroidal space. Similarly, anchoring of the shunt to the tissue adjacent the suprachoroidal space may also result in formation of a cyclodialysis cleft.